<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <button class="btn" disabled>点击(5)</button>
  <script>
    const btn = document.querySelector('.btn')
    let i = 5

    let n =  setInterval(function(){
        i--
        btn.innerHTML = `点击(${i})`
        if(i === 0){
            clearInterval(n)
            btn.disabled = false
            btn.innerHTML = '同意'
        }
    },1000)
    
  </script>
</body>
</html>